Bi-Functional Crops: Fall-sown cool season grain legumes provide cover crop attributes

Cool season food legumes (CSFL) harvested as seed are important rotational crops in the Palouse region of WA and ID and western WA as they provide fixed N to subsequent crops and break weed and disease cycles. In organic systems, fall-sown CSFL can serve as winter cover crops to reduce soil erosion, improve soil health and avoid excessive phosphorus from manure or compost. Overwintering CSFL provide farmers maximum nitrogen contribution by plow-down, would shift field work from wet, unreliable spring to drier fall months and produce greater biomass than spring-sown CSFL. Additionally, they attract beneficial pollinators in the spring. Significant advances have been made improving CSFL and new cultivars have cold tolerance equivalent to winter wheat. Despite these advantages, little work has been done to characterize, breed or develop CSFL varieties with desirable cover crop attributes.
This project will identify pea and faba breeding lines and germplasm with desirable cover crop/green manure attributes: good overwintering, high biomass production and early spring N fixation. Previously, we developed fall-sown lines of pea and faba bean with good winter-hardiness and seed yield, but neither N fixation nor biomass production was characterized. We will evaluate 10 entries each of pea and faba bean at four sites in a replicated RCBD. Lines will be evaluated for seedling establishment, early fall growth and vigor, winter survival, and early spring biomass. Plants (roots and shoots) from each plot will be collected in the spring, and biomass and its N content will be measured. Agronomic practices including seeding date, rate, and depth will be evaluated.
Priority topics addressed: ‘Organic approaches to sustainable soil quality’; ‘Breeding, selection, management practices’; ‘Innovation/diversification to increase resiliency and sustainability’.